Oil Supply Device

ABSTRACT

An oil supply device for a motor vehicle transmission ( 2 ) with gear wheels provided on shafts, with bearings in which gearwheels and shafts are pivoted, and with synchronization devices ( 10 ), which can be moved into the desired shifting positions by actuation of a shifting lever via selector shafts and shifting forks, wherein a shaft ( 4 ) has an axially extending central borehole ( 6 ) and at least one transverse borehole ( 8 ) for oil supply, has boreholes ( 14 ) in a synchronous element ( 12 ) of the synchronization device ( 10 ) as well as a retaining plate ( 16 ) with a sickle-shaped recess ( 18 ).

This application is a national stage completion of PCT/EP2005/006175 filed Jun. 9, 2005 which claims priority from German Application Serial No. 10 2004 031 471.3 filed Jun. 30, 2004.

FIELD OF THE INVENTION

The invention relates to an oil supply device.

BACKGROUND OF THE INVENTION

In motor vehicle transmissions, and particularly in manual transmissions, the lubrication of gear teeth, bearings and idler gear bearings situated on and in shafts has a particular significance due to the complex design of motor vehicle transmissions. On one hand, sufficient lubrication of the gear teeth and bearings must be achieved; on the other, the smallest amount of oil possible must guarantee a small drag torque to attain good shifting properties, which greatly influence shifting comfort, particularly with manual transmissions. The oil temperatures are also to remain moderate, and oil supply to the reverse gear wheel and well as the cold shifting ability of the transmission must be guaranteed. Various types of oil pumps, hollow-bored shafts and oil lines are used to solve the problems associated therewith, or oil line baffles, oil boreholes and/or increased oil levels are used in motor vehicles. When dipping the gear wheels into the oil, the latter is arbitrarily distributed in the motor vehicle transmission, depending upon the rotational speed, gear and driving state of the motor vehicle. Stationary oil line devices may be used in an attempt to guide the oil selectively. With oblique gearing of the components, the oil in the oil sump is pumped in the direction specified by the oblique gearing, resulting in varying accumulation of oil in the oil sump.

An oil lubrication system for a motor vehicle transmission is known from DE 32 38 790 C1 in which a centrifugal pump is used, which guides the oil radially toward the outside through openings in radially directed guide channels. Subsequently, the oil can reach the interior of a hollow-bored drive shaft via an annular groove. Although this system guarantees effective supply with lubricating oil distribution, it has the disadvantage that the necessary centrifugal pump requires installation space, which is not always available, as well as high sealing expenses.

Furthermore, an oil lubrication system for motor vehicle transmissions is known from DE 195 01 799 C2, comprising an annular chamber, to which lubricant and cooling oil are fed, a rotating drive shaft and a pump element for the lubricating and cooling oil, wherein at least one lubricating oil borehole is provided axially offset in the rotating drive shaft, and the pump element is formed by a collection and a baffle plate, which is firmly connected to the transmission housing, which substantially occupies the cross-sectional area of the chamber and is shaped such that the oil pumped by the rotating drive shaft is retained at the collection and baffle plate while building pressure, as a result of which the lubricating and cooling oil is pressed into the axially offset lubricating oil borehole. This solution also disadvantageously requires relatively high sealing expenses, particularly between the drive shaft and the interior of the transmission housing.

A further oil feeding device for feeding of lubricating and cooling oils from a housing to a rotating shaft is known from DE 39 27 775 C2, wherein two sealing rings are required on the shaft, which rings are disposed at an axial distance from each other, with sealing points being formed between the sealing rings and two sealing surfaces provided substantially radially in the housing at an axial distance from each other. Here the sealing rings are subject to the prestressing of the oil pressure present between the sealing rings. In this case, the sealing expenses are very high, resulting in high manufacturing and assembly costs.

A shifting fork for a change speed gearbox is described in DE 196 02 041 A1, which fork has a device for feeding splash oil to the synchronization device, which is actuated by the shifting fork. Here, merely an overload of the synchronization device is to be avoided in that a directed sequence of the device is provided, which supplies the synchronizing device with additional oil during synchronization. This device for supplying splash oil spray, however, does not ensure better lubrication of a large number of components in the motor vehicle transmission.

In particular, increasing the performance of passenger car motors, which results in increased power loss of gear boxes, which in turn results in an increase in heat to be discharged through the housing, requires alternative lubricating concepts in relation to the presently common oil sump or splash lubrication used in gearboxes. Furthermore, the aerodynamic optimization of motor vehicles and the associated encapsulation of the underbody assembly increasingly impede the transfer of heat through the housing.

It is the object of the invention to implement an oil supply device for a motor vehicle transmission, particularly in a manual motor vehicle transmission, to improve the lubrication of components in order to guarantee sufficient lubrication of the components, even at very high rotational speeds.

SUMMARY OF THE INVENTION

The object of the invention is achieved with an oil supply device of this type. The oil reaches a synchronizing device though transverse boreholes via an axially extending central borehole in a shaft of the motor vehicle transmission. By adding boreholes to a synchronous element of a synchronization device in combination with a sickle-shaped recess in a retaining plate of a bearing of the shaft, the volume between the synchronizing device and the bearing is reduced upon rotational motion and oil flowing in the direction of rotation. A partial volume flow of the oil is fed through boreholes in the shaft and synchronous element to the components to be lubricated, for example support areas. Excess oil can escape radially as lost oil between the synchronizing device and bearing. So as to reduce the losses, the synchronous element must be closed with a plate axially on the side facing away from the bearing. The oil supply in the closed shaft can be used for lubricating support areas. For this, additional radial boreholes are introduced into the shaft in the region of the running surfaces of the bearings of the gears. The synchronous element has recesses on the side facing the bearing, in which recesses lugs of an insert for the synchronous element are braced. Grooves are provided in thrust washers of the gear wheels, which grooves allow the oil to escape from all support areas of the gear wheels. The interaction of these measures brings about a significant improvement in the lubrication of components in the motor vehicle transmission, even at very high rotational speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 shows a partial section of a transmission with an oil supply device according to the invention, and

FIG. 2 represents a plan view of the motorvehicle transmission represented in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 depicts a partial section of a motor vehicle transmission 2 according to the invention with a shaft 4, which has an axially extending central borehole 6. Oil reaches a synchronization device 10 through transverse boreholes 8. A synchronous element of the synchronizing device 10 has a borehole 14, which in conjunction with a retaining plate 16, having a sickle-shaped recess 18, ensures that the volume between the synchronization device 10 and bearing 28 is reduced upon rotational motion and with oil flowing in the direction of rotation. A partial volume flow of the oil is fed through a central borehole 6 in the shaft 4, the transverse borehole 8 and the borehole 14 in the synchronous element 12 to the components to be lubricated, here, for example, a bearing 20. Excess oil can escape radially as lost oil between the synchronization device 10 and bearing 20. A running surface 24 of the gear 26 can be provided with additional oil through a transverse borehole 22. The synchronous element 12 has grooves 30 on the side facing the bearing 28, in which grooves lugs 32 of an insert 34 are braced. A thrust washer 36 between the gear wheel 26 and a gear wheel 38 has grooves 40, as a result of which improved oil supply of a bearing 42 of the gear wheel 38 is attained.

FIG. 2 shows a housing with the bearing 28 pressed into the housing and an embodiment of a retaining plate 16 with a sickle-shaped recess 18.

REFERENCE NUMERALS

-   2 motor vehicle transmission -   4 shaft -   6 central borehole -   8 transverse borehole -   10 synchronization device -   12 synchronous element -   14 borehole -   16 retaining plate -   18 sickle-shaped recess -   20 bearing -   22 transverse borehole -   24 running surface -   26 gear wheel -   28 bearing -   30 groove -   32 lug -   34 insert -   36 thrust washer -   38 gear wheel -   40 groove -   42 bearing 

1-4. (canceled)
 5. A device for supplying oil to a motor vehicle transmission (2) having gear wheels disposed on shafts, bearings which rotationally support the gear wheels and the shafts, and synchronization devices (10) which are displaced into desired shifting positions by actuation of a shifting lever via one or more of selector shafts and shifting forks, the device comprising a shaft (4) having an axially extending central borehole (6) and at least one radially extending borehole (8) for directing an oil supply, a synchronous element (12) of the synchronization device (10) having boreholes (14), a retaining plate (16) located between the synchronization device (10) and a bearing (28), the retaining plate (16) having a sickle-shaped recess (18), and the synchronous element (12) having grooves (30) in which lugs (32) of an insert (34) are braced.
 6. The oil supply device according to claim 5, wherein the synchronous element (12) is axially closed at a first end opposed to a second end adjacent a bearing (20), with a plate.
 7. The oil supply device according to claim 5, wherein the shaft (4) has at least one radially extending borehole (22) in a region of a running surface (24) of the gear wheel (26).
 8. The oil supply according to claim 5, wherein a thrust washer (36) is located between a first gearwheel (26) and a second gearwheel (38), and has grooves (40).
 9. A device for supplying oil to a motor vehicle transmission (2), the transmission having a plurality of gear wheels disposed at least one shaft, a plurality of bearings which rotationally support the gear wheels and the at least one shaft, and at least one synchronization device (10) which is displaced into desired shifting position, by actuating a shifting lever via one or more of selector shafts and shifting forks, the device comprising: a shaft (4) having an axially extending central borehole (6) and at least one radial borehole (8) for directing an oil supply, the at least one radial borehole extending radially between the central borehole and an exterior of the shaft to a running surface (24) of a first gear wheel (26); a synchronous element (12) of the synchronization device (10) having at least one axially extending boreholes (14) for directing the oil supply, and a plurality of grooves (30) in which lugs (32) of an insert (34) are braced; a retaining plate (16) located between the synchronization device (10) and a first bearing (28), the retaining plate (16) having a sickle-shaped recess (18); the synchronous element (12) being axially closed by a plate on a first end opposed to a second end adjacent a bearing (20); and a thrust washer (36) is located between the first gear wheel (26) and a second gear wheel (38) and has grooves (40). 